Granulocyte transfusions are felt to play an important role in the therapy of bacterial infections in neutropenic patients. However, there are no means at present to assess quantitatively their clinical effectiveness or the in vivo function of donor granulocytes after transfusion. We have developed models of focal bacterial infection (bacterial keratitis) and systemic infection in neutropenic guinea pigs which allow quantitative assessment of transfused granulocyte bactericidal capacity. We propose to use these methods and new techniques for measuring chemotaxis of donor cells in vivo to assess transfusion effectiveness and in vivo granulocyte function. Using these methods we will determine the effect of donor/recipient tissue matching and allo-immunization upon transfused polymorphonuclear leukocyte (PMN) function and kinetics. Additionally, we will determine the effect of storage and collection techniques upon transfused granulocytes. These new in vivo assays of PMN function will be correlated with established in vitro assays of granulocyte function and metabolism. Our studies will provide the basis for possible alterations in currently employed granulocyte transfusion techniques and will suggest method to improve the clinical effectiveness of human granulocyte transfusions.